During hemodialysis, diffusion ceases to occur when

During hemodialysis, diffusion ceases to occur when

• A. When the dialysate runs out
• B. When blood flow stops
• C. Until the concentration of each electrolyte in the patient's blood equals the concentration in the dialysate
• D. After a fixed time of treatment

Answer: (C)

Diffusion in hemodialysis relies on concentration differences across the membrane. Solutes move from blood to dialysate as long as there is a gradient. When the concentration of each electrolyte in the patient’s blood becomes equal to the concentration in the dialysate, there is no longer a driving force, so diffusion stops. Different solutes reach equilibrium at different rates, but diffusion ends once equilibrium is achieved for those solutes. Time or running out of dialysate aren’t the fundamental triggers—the halting factor is the loss of the concentration gradient.

Diffusion in hemodialysis relies on concentration differences across the membrane. Solutes move from blood to dialysate as long as there is a gradient. When the concentration of each electrolyte in the patient’s blood becomes equal to the concentration in the dialysate, there is no longer a driving force, so diffusion stops. Different solutes reach equilibrium at different rates, but diffusion ends once equilibrium is achieved for those solutes. Time or running out of dialysate aren’t the fundamental triggers—the halting factor is the loss of the concentration gradient.